Apparatus to reduce polymers deposition

ABSTRACT

Implementations of the present disclosure provide a process kit for an electrostatic chuck. In one implementation, a substrate support assembly is provided. The substrate support assembly includes an electrostatic chuck having a first recess formed in an upper portion of the electrostatic chuck. A process kit surrounds the electrostatic chuck. The process kit includes an inner ring and an outer ring disposed radially outward of the inner ring. The outer ring includes a second recess formed in an upper portion of the upper ring. The inner ring is positioned within and is supported by the first recess and the second recess. An upper surface of the inner ring and an upper surface of the outer ring are co-planar.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Application Ser. No.62/776,925, filed Dec. 7, 2018, which is incorporated by reference inits entirety.

FIELD

Examples of the present disclosure generally relate to apparatuses forprocessing substrates, such as semiconductor substrates. Moreparticularly, a process kit for an electrostatic chuck is disclosed.

BACKGROUND

In the processing of substrates, such as semiconductor substrates anddisplay panels, a substrate is placed on a substrate support in aprocess chamber while suitable process conditions are maintained in theprocess chamber to deposit, etch, form layers on, or otherwise treatsurfaces of the substrate. During etching processes, a plasma, whichdrives the etching process, may not be uniformly distributed across thesubstrate surface. The non-uniformity is particularly apparent at theedge of the substrate surface. This non-uniformity contributes to poorprocessing results. Thus, some process chambers use edge rings, whichmay also be referred to as a process kit ring, in order to increaseplasma uniformity and improve process yield.

However, it has been observed that the etching process can result inaccumulation of polymer material at the edge of the substrate surface.The polymer material may get stuck in the gap between the edge of thesubstrate and the process kit ring and diffuse into the electrostaticchuck of the substrate support. When the substrate is lifted up and/orthe plasma is turned off, the polymer material may deposit back onto thesubstrate surface, thereby negatively affecting substrate processing.

Therefore, there is a need in the art for apparatuses that can addressissues discussed above.

SUMMARY

In one implementation, a substrate support assembly is provided. Thesubstrate support assembly includes an electrostatic chuck having afirst recess formed in an upper portion of the electrostatic chuck. Aprocess kit surrounds the electrostatic chuck. The process kit includesan inner ring and an outer ring disposed radially outward of the innerring. The outer ring includes a second recess formed in an upper portionof the upper ring. The inner ring is positioned within and is supportedby the first recess and the second recess. An upper surface of the innerring and an upper surface of the outer ring are co-planar.

In another implementation, a substrate support assembly for processing asubstrate is provided. The substrate support assembly includes asubstrate support and an electrostatic chuck disposed on the substratesupport. The electrostatic chuck includes a first recess formed in anupper portion of the electrostatic chuck. A process kit surrounds theelectrostatic chuck. The process kit includes an inner ring and an outerring disposed radially outward of the inner ring. The outer ringincludes a second recess formed in an upper portion of the upper ring.The inner ring is positioned within and is supported by the first recessand the second recess. An upper surface of the outer ring is higher thanan upper surface of the inner ring. A plurality of pumping channels areformed through the outer ring. The pumping channels are angleddownwardly towards a direction away from the inner ring.

In yet another implementation, a method of removing particles from asubstrate support surface includes arranging a top surface of an outerring coplanar with a top surface of an inner ring. An outer ring isdisposed radially outward of the inner ring. The outer ring includes afirst upper surface and a second upper surface. The first upper surfaceis co-planar with the upper surface of the inner ring. A plurality ofprotrusions is symmetrically arranged on an inner ring. The plurality ofprotrusions utilized for positioning a substrate on a substrate surface.Pumping channels are arranged on the outer ring. The pumping channelsare configured to pump unwanted material away from the substratesupport.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toaspects of the disclosure, some of which are illustrated in the appendeddrawings. It is to be noted, however, that the appended drawingsillustrate only typical aspects of this disclosure and are therefore notto be considered limiting of its scope, for the disclosure may admit toother symmetrically effective aspects.

FIG. 1 is a schematic sectional view of a process chamber according toone example of the disclosure.

FIG. 2 is an enlarged schematic view of the substrate support assemblyof process chamber according to one example described herein.

FIG. 3 illustrates a simplified perspective view of an inner ringshowing protrusions.

FIG. 4A illustrates a cross-sectional view of a process kit according toone implementation.

FIG. 4B illustrates a perspective view of a pumping ring showingprotrusions.

FIG. 5 illustrates a cross-sectional view of a process kit according toone implementation.

FIG. 6A illustrates a cross-sectional view of a process kit according toone implementation.

FIG. 6B illustrates a perspective view of a portion of a process kitshowing pumping channels.

FIG. 7 is a flow chart of an exemplary method of removing contaminantsfrom the surface of the substrate support.

To facilitate understanding, identical reference numerals have beenused, wherever possible, to designate identical elements that are commonto the Figures. Additionally, elements of one example may beadvantageously adapted for utilization in other examples describedherein.

DETAILED DESCRIPTION

Implementations of the present disclosure provide a process kit for asubstrate support assembly that includes an electrostatic chuck that isdisposed on a top surface of a substrate support. The process kitsurrounds the electrostatic chuck and includes an inner ring and anouter ring that are concentrically positioned with respect to thesubstrate support. The upper surfaces of the inner ring and the outerring can be co-planar or at different heights, and the outer ring mayinclude pumping channels to help exhaust unwanted polymer material fromedges of the process kit and the electrostatic chuck, thereby improvingquality of the substrate and process yield.

FIG. 1 is a schematic sectional view of a process chamber 100, accordingto one example of the disclosure. The illustrated process chamber 100 issuitable for etching, chemical vapor deposition (CVD), or otherplasma-based processes. The process chamber 100 includes a chamber body101 and a lid 103 disposed thereon. The chamber body 101 and the lid 103together define an inner volume. The chamber body 101 is typicallycoupled to an electrical ground 107. A substrate support assembly 111 isdisposed within the inner volume to support a substrate 109 thereonduring processing. The process chamber 100 also includes an inductivelycoupled plasma apparatus 102 for generating a plasma within the processchamber 100, and a controller 155 adapted to control operations of theprocess chamber 100.

The substrate support assembly 111 includes one or more electrodes 153coupled to a bias source 119 through a matching network 120 tofacilitate biasing of the substrate 109 during processing. The biassource 119 may be a source of up to about 1000 W (but not limited toabout 1000 W) of RF energy at a frequency of, for example, approximately13.56 MHz, although other frequencies and powers may be provided asdesired for particular applications. The bias source 119 may be capableof producing either or both of continuous or pulsed power. In someexamples, the bias source 119 may be a DC or pulsed DC source. In someexamples, the bias source 119 may be capable of providing multiplefrequencies. The one or more electrodes 153 may be coupled to a chuckingpower source 160 to facilitate chucking of the substrate 109 duringprocessing. The substrate support assembly 111 includes a process kit(not shown) surrounding the substrate 109. Various implementations ofthe process kit will be described in more detail below.

The inductively coupled plasma apparatus 102 is disposed above the lid103 and is configured to inductively couple RF power into the processchamber 100 to generate a plasma within the process chamber 100. Theinductively coupled plasma apparatus 102 includes first and second coils110, 112 disposed above the lid 103. The relative position, ratio ofdiameters of each coil 110, 112, and/or the number of turns in each coil110, 112 can each be selected as desired to control the profile ordensity of the plasma being formed. Each of the first and second coils110, 112 is coupled to an RF power supply 108 through a matching network114 via an RF feed structure 106. The RF power supply 108 may be capableof producing up to about 4000 W (but not limited to about 4000 W) at atunable frequency in a range from 50 kHz to 13.56 MHz, although otherfrequencies and powers may be utilized as desired for particularapplications.

In some examples, a power divider 105, such as a dividing capacitor, maybe provided between the RF feed structure 106 and the RF power supply108 to control the relative quantity of RF power provided to therespective first and second coils. In some examples, the power divider105 may be incorporated into the matching network 114.

A heater element 113 may be disposed atop the lid 103 to facilitateheating the interior of the process chamber 100. The heater element 113may be disposed between the lid 103 and the first and second coils 110,112. In some examples, the heater element 113 may include a resistiveheating element and may be coupled to a power supply 115, such as an ACpower supply, configured to provide sufficient energy to control thetemperature of the heater element 113 within a desired range.

During operation, the substrate 109, such as a semiconductor wafer orother substrate suitable for plasma processing, is placed on thesubstrate support assembly 111 and process gases supplied from a gaspanel 116 through entry ports 117 into the inner volume of the chamberbody 101. Additionally or alternatively, the process gases may besupplied into the inner volume of the chamber body 101 through entryports (not shown) disposed in the lid 103. In either case, the processgases are ignited into a plasma 118 in the process chamber 100 byapplying power from the RF power supply 108 to the first and secondcoils 110, 112. In some examples, power from a bias source 119, such asan RF or DC source, may also be provided through a matching network 120to electrodes 153 within the substrate support assembly 111. Thepressure within the interior of the process chamber 100 may becontrolled using a valve 121 and a vacuum pump 122. The temperature ofthe chamber body 101 may be controlled using liquid-containing conduits(not shown) that run through the chamber body 101.

The controller 155 is configured to control the operation of the processchamber 100 during processing. The controller 155 includes a centralprocessing unit (CPU) 123, a memory 124, and support circuits 125 forthe CPU 123 and facilitates control of the components of the processchamber 100. The controller 155 may be one of any form ofgeneral-purpose computer processor that can be used in an industrialsetting for controlling various chambers and sub-processors. The memory124 stores software (source or object code) that may be executed orinvoked to control the operation of the process chamber 100 in themanner described herein.

FIG. 2 is an enlarged schematic view of the substrate support assembly111 of process chamber 100 according to one example described herein.The substrate support assembly 111 includes a process kit 203, asubstrate support 205, and an electrostatic chuck 229. The electrostaticchuck 229 is disposed on a top surface of the substrate support 205 andsurrounded by the process kit 203. The substrate support 205 includes aground plate 226 surrounding an insulating plate 227 and a facilitiesplate 228 assembled in a vertical stack. The substrate support 205further includes a sleeve 230 circumscribing the facilities plate 228and the electrostatic chuck 229 to insulate the RF hot electrostaticchuck 229 from the ground plate 226. The sleeve 230 may be fabricatedfrom quartz.

The facilities plate 228 is positioned above a lower portion of theground plate 226 and between the insulating plate 227 and theelectrostatic chuck 229. The electrostatic chuck 229 may include aplurality of electrodes 153 (four are shown) embedded in an insulatingmaterial 236. The electrodes 153 are coupled to the chucking powersource 160 (shown in FIG. 1) to facilitate chucking of the substrate 109to an upper surface 233 of the electrostatic chuck 229. One or moreheating or cooling channels may optionally be formed in the insulatingmaterial 236 to facilitate temperature control of the substrate 109during processing. In some aspects, the electrodes 153 are cathodescoupled through the matching network 120 to the bias source 119 (shownin FIG. 1).

The process kit 203 includes a cover ring 246, an inner ring 242, and anouter ring 244, which are arranged concentrically with respect to anaxis passing through a center of the substrate support assembly 111. Insome examples, the cover ring 246 is optional and may not be required.In cases where the cover ring 246 is used, the cover ring 246 can bepositioned on an upper surface 241 of the outer ring 244. The cover ring246 surrounds the radially-outward edges of the substrate 109. In someexamples, the cover ring 246 is sized to abut against the edges of thesubstrate 109. The cover ring 246 facilitates protection of the edges ofthe substrate 109 during processing, and additionally, provides lateralsupport to the substrate 109 during processing. The cover ring 246 maybe fabricated from quartz, silicon, or any other plasma-resistantmaterial. The inner ring 242 may be fabricated from silicon or any otherplasma-resistant material. In a particular example, the inner ring 242is fabricated from silicon carbide (SiC). The outer ring 244 may befabricated from quartz, silicon, or any other plasma-resistant material.In one example, the inner ring 242 is fabricated from silicon and theouter ring 244 is fabricated from quartz.

The outer ring 244 is disposed radially outward of the inner ring 242.The outer ring 244 is positioned on an upper surface of the verticaledge of the ground plate 226. The outer ring 244 includes a bottomrecess 231 formed in a bottom surface of the outer ring 244 for engagingthe sleeve 230. The outer ring 244 may also include an upper recess 249formed in the upper surface 241 of the outer ring 244 to facilitatepositioning of the cover ring 246. While the substrate 109 is shown tohave the radially-outward edges extending over an upper surface 245 ofthe inner ring 242, it is contemplated that the radially-outward edgesof the substrate 109 and the upper surface 245 may not overlap. That is,the radially-outward edges of the substrate 109 may stop at the edge ofthe upper portion of the electrostatic chuck 229.

The inner ring 242 is supported commonly by the electrostatic chuck 229and the outer ring 244. The inner ring 242 is positioned in a way thatthe upper surface 245 of the inner ring 242 and the upper surface 241 ofthe outer ring 244 are co-planar. For example, a portion of the innerring 242 is positioned within and supported by a recess 235 of theelectrostatic chuck 229. The recess 235 may be formed in the outerperiphery of the upper portion of the electrostatic chuck 229. Theremainder of the inner ring 242 is positioned within and supported by arecess 237 of the outer ring 244. The recess 237 may be formed in theinner periphery of the upper portion of the outer ring 244. The topsurface of the recess 235 and the top surface of the recess 237 are atthe same elevation.

The upper surface 245 of the inner ring 242 and the upper surface 241 ofthe outer ring 244 are co-planar, or at the same height, to facilitatepumping of unwanted polymer materials (accumulated between the processkit 203 and the edges of the electrostatic chuck 229) to the vacuum pump122 (see FIG. 1). The inner ring 242 may be stationary with respect tothe substrate 109 during processing.

The radially-outward edge of the inner ring 242 may be separated from avertical wall of the recess 237 by a gap “D1” to allow thermal expansionof the inner ring 242 and/or the outer ring 244. The gap “D1” may be ina range from about 0.002 inches to about 0.030 inches, for example about0.010 inches to about 0.020 inches, which may vary depending on thematerial utilized for the inner and outer rings 242, 244. The size ofgap “D1” can be chosen to prevent deposition of polymer material at theradially-outward edges of the inner ring 242. In some examples, theradially-outward edge of the inner ring 242 is in contact with thevertical wall of the recess 237.

The outer ring 244 is positioned concentrically with respect to theinner ring 242 and the substrate 109. The outer ring 244 assists theinner ring 242 in providing the substrate 109 with lateral support andreducing undesired etching of the inner ring 242. In some examples, theupper surface 245 of the inner ring 242 may be provided with a pluralityof protrusions 243 (only one is shown) to prevent the substrate 109 fromsliding during the processing. FIG. 3 illustrates a simplifiedperspective view of the inner ring 242 and the outer ring 244, showingthree protrusions 243 are symmetrically disposed around thecircumference of the inner ring 242 to confine movement of the substrate109. It is contemplated that any number of protrusions 243 may be used.The protrusions 243 may be spherical caps, cylinders, raised dots, orhave any other suitable geometry. The protrusions 243 may be fabricatedfrom the same or different material from the inner ring 242. In oneexample, the protrusions 243 are fabricated from silicon carbide.

The substrate support assembly 111 may optionally include one or moreactuators 247, such as a stepper motor or linear actuator, among others.For example, the one or more actuators 247 are disposed in the groundplate 226. It is contemplated, however, that the actuator 247 may bepositioned externally of the substrate support assembly 111. Eachactuator 247 is adapted to engage, or interface with, one or more pushpins 248. The one or more push pins 248 extend from the ground plate226, through the insulating plate 227 and the sleeve 230, and intocontact with the outer ring 244. Actuation of the one or more push pins248 results in vertical actuation, or displacing, of the outer ring 244,the inner ring 242, and the cover ring 246 (if used) relative to anupper surface of the substrate 109. The position of the outer ring 244may be adjusted to a height which accommodates for erosion of the outerring 244 in order to increase plasma uniformity across a substratesurface during processing.

The substrate support assembly 111 also includes three or more lift pins288 for lifting the substrate 109 off the surface of the electrostaticchuck 229. The lift pins 288 extend from the ground plate 226, theinsulating plate 227, the facilities plate 228 and through theelectrostatic chuck 229 to the respective lift pin hole 286 (FIG. 3).The lift pins 288 are controlled by an actuator 284. Each actuator 284is adapted to engage, or interface with the lift pins 288 to move themup and/or down.

One or more bellows may be positioned around each of the one or morepush pins 248 to reduce particle contamination within the processchamber 100 (shown in FIG. 1). Additionally, one or more push pin guides239, such as a guide sleeve or bearing, may be positioned in the sleeve230 disposed around each push pin 248 to facilitate actuation of eachpush pin 248. The push pin guides 239 provide bearing surfaces for pushpins 248. The actuation of push pins 248 can be operably controlled bythe controller 155 (shown in FIG. 1).

In one example, the one or more actuators 247 are micro-stepper motors.In another example, the one or more actuators 247 are piezo-electricmotors. In one example, the one or more push pins 248 are fabricatedfrom quartz or sapphire.

In one example, the controller may be a general purpose computer thatincludes memory for storing software. The software may includeinstructions for detecting erosion of the inner ring 242 and outer ring244 and then directing the one or more actuators 247 to raise the one ormore push pins 248 such that the inner ring 242 and the outer ring 244are elevated to a desired height.

FIG. 4A illustrates a cross-sectional view of a process kit 400according to one implementation. The process kit 400 can be used inplace of the process kit 203 of FIG. 2. The process kit 400 includes aninner ring 442, an outer ring 444, and a pumping ring 446. The outerring 444 is disposed radially outward of the inner ring 442. The innerring 442 and the outer ring 444 are similar in design as the inner ring242 and the outer ring 244 except that the entire upper surface 441 ofthe outer ring 444 and the entire upper surface 445 of the inner ring442 are co-planar or at the same elevation.

The pumping ring 446 is disposed over the outer ring 444. The pumpingring 446 may have three or more protrusions 448 disposed at the bottomsurface of the pumping ring 446. The protrusions 448 create a gap “D2”between the outer ring 444 and the pumping ring 446 to allow passage ofunwanted polymer materials (accumulated between the process kit 400 andthe edges of the electrostatic chuck 229), which are then pumped out ofthe process chamber through the vacuum pump 122 (FIG. 1). Theprotrusions 448 may be symmetrically arranged around the circumferenceof the pumping ring 446. FIG. 4B illustrates a perspective view of thepumping ring 446 showing six protrusions 448 are disposed at the bottomsurface 450 of the pumping ring 446. Any number of protrusions may beused to obtain desired and/or maximum pumping area.

The gap “D2” may be in a range of about 0.002 inches to about 0.1inches, such as about 0.010 inches to about 0.050 inches. In alternativeimplementations, the protrusions 448 can be provided at the uppersurface 441 of the outer ring 444 to create the gap “D2” for the samepurposes. In either case, the size of gap “D2” can be selected to changepumping efficiency. The pumping ring 446 may be fabricated from quartz,silicon, or any other plasma-resistant material. The inner ring 442 andthe outer ring 444 may be fabricated from the same material as the innerring 242 and the outer ring 244 as discussed above.

FIG. 5 illustrates a cross-sectional view of a process kit 500 accordingto one implementation. The process kit 500 includes an inner ring 542and an outer ring 544 disposed radially outward of the inner ring 542.In this implementation, the inner ring 542 and the outer ring 544 aresimilar in design as the inner ring 242 and the outer ring 244 exceptthat the outer ring 544 has a first upper surface 541 and a second uppersurface 543. The first upper surface 541 is co-planar with an uppersurface 545 of the inner ring 542. The second upper surface 543 has aslope towards a direction away from the inner ring 542. In someexamples, the entire upper surface of the outer ring 544 may be a slope.The longitudinal axis of the second upper surface 543 can be at an angle“a” with respect to a direction extending along an outer peripheralsurface 547 of the outer ring 544. In one implementation, the angle “a”is in a range of about 35 degrees to about 85 degrees, such as about 45degrees to about 75 degrees, for example about 60 degrees. Comparing toouter rings having an entire planar upper surface (e.g., process kit400), the slope of the second upper surface 543 allows unwanted polymermaterials (accumulated between the process kit 500 and the edges of theelectrostatic chuck 229) to be pumped to the vacuum pump 122 moreefficiently.

FIG. 6A illustrates a cross-sectional view of a process kit 600according to one implementation. The process kit 600 includes an innerring 642 and an outer ring 644 disposed radially outward of the innerring 642. A plurality of protrusions 643 are disposed at an uppersurface 645 of the inner ring 642. Similar to the protrusions 243, theprotrusions 643 can help positioning of the substrate (not shown) duringthe process. The process kit 600 may optionally include a cover ring 646positioned on an upper surface 641 of the outer ring 644. The inner ring642, the outer ring 644 and the cover ring 646 (if used) are similar indesign as the inner ring 242, the outer ring 244, and the cover ring 246except that the upper surface 641 of the outer ring 644 is higher thanthe upper surface 645 of the inner ring 642 by a distance “D3”. In oneimplementation, the distance “D3” may be in a range of about 0.01 inchesto about 5 inches, such as about 0.1 inches to about 2 inches, forexample about 1 inch.

In one implementation, which can be included or combined with any otherimplementations discussed in this disclosure, the outer ring 644 furtherincludes a plurality of pumping channels 647 formed through the outerring 644. The pumping channels 647 may extend from a vertical wall 639of a recess 637 formed in the inner periphery of the upper portion ofthe outer ring 644, to an outer peripheral surface 653 of the outer ring644. The pumping channels 647 may be angled downwardly towards adirection away from the inner ring 642. For example, a longitudinaldirection of the pumping channels 647 can be at an angle “β” withrespect to a direction extending along the outer peripheral surface 653.In one implementation, the angle “β” is in a range of about 30 degreesto about 88 degrees, such as about 40 degrees to about 65 degrees, forexample about 50 degrees. The unwanted polymer materials or particlesaccumulated between the process kit 600 and the edges of theelectrostatic chuck 229 can be pumped to the vacuum pump 122 (FIG. 1)through the pumping channels 647.

FIG. 6B illustrates a perspective view of a portion of the process kit600 showing pumping channels 647 are formed in the vertical wall 639located at the upper portion of the outer ring 644. The pumping channels647 may be disposed symmetrically around the circumference of the outerring 644. The pumping channels 647 may have any suitable shape, such asround, square, triangular, etc. The diameter of the pumping channels 647may be in a range from about 0.1 inches to about 1 inches.

Implementations of the present disclosure result in improved quality ofa substrate being processed in a process chamber as unwanted polymermaterial accumulated at edges of a process kit and the electrostaticchuck can be exhausted more efficiently through pumping channels formedin an outer ring of the process kit. The improved quality of thesubstrate leads to an increase in process yield. Furthermore, processchambers making use of the present disclosure experience less downtimefor preventative maintenance by extending the usable life of processkit.

FIG. 7 is a flow chart of an exemplary method 700 of removingcontaminants from the surface of the substrate support, i.e.electrostatic chuck 229.

At block 704, the plurality of protrusions 243 is symmetrically arrangedon the upper surface 245 of the inner ring 242. As shown in FIGS. 2 and3, the protrusions 243 are symmetrically disposed around thecircumference of the inner ring 242 to confine movement of the substrate109. At block 708, the upper surface 241 of the outer ring 244 isarranged coplanar with the upper surface 245 of the inner ring 242. Aspreviously stated, pumping of unwanted polymer materials is facilitatedby arranging the upper surface 245 of the inner ring 242 coplanar to theupper surface 241 of the outer ring 244. In one configurationillustrated along path 701, the gap D2 (i.e. channel) can be oriented ina horizontal direction to facilitate pumping of unwanted material, asshown in FIG. 4. At block 712, channels 647 are provided through theouter ring 244. As illustrated along path 703, the channels 647 areconfigured to pump unwanted material away from substrate support (e.g.the electrostatic chuck 229). As noted above, the channels 647 arefurther configured to pump unwanted material away from the process kit203. In the example shown in FIGS. 6A-6B, the channels 647 have circularor ovular cross-section areas. In another example, the channels havesquare or rectangular cross-sectional areas (not shown). At block 716,channels 647 are positioned at an acute angle “β,” away from the innerring 642. A portion of the channel 647 may be positioned below thesubstrate 109. The substrate 109 is positioned on the upper surface 233of the electrostatic chuck 229. The upper surface 233 is substantiallycoplanar to the upper surface 245 of the inner ring 242. As statedabove, angle “β,” is taken with respect to a direction extending alongthe outer peripheral surface 653. Path 705 demonstrates another examplethat includes block 720. At block 720, a slanted surface 543 is providedon the outer ring 244 at an acute angle “a” below the first uppersurface 541 of the outer ring 544, as shown in FIG. 5. At block 724, acover ring 246 is arranged above the outer ring 244. At block 728, thegap D2 is formed between the upper surface 241 of the outer ring 244 andthe bottom surface of the pumping ring 446. As noted above, the gap D2(i.e. channel) allows passage of unwanted polymer materials away fromthe substrate support and the process kit 400. As shown in FIG. 4, in atleast one example, protrusions 448 may be symmetrically arranged aroundthe circumference of the pumping ring 446 (e.g. outer ring 244) creatingthe gap D2.

While the foregoing is directed to implementations of the presentdisclosure, other and further implementations of the disclosure may bedevised without departing from the basic scope thereof.

1. A substrate support assembly, comprising: an electrostatic chuckcomprising a first recess formed in an upper portion of theelectrostatic chuck; and a process kit surrounding the electrostaticchuck, wherein the process kit comprises: an inner ring; and an outerring disposed radially outward of the inner ring, wherein the outer ringcomprises a second recess formed in an upper portion of an upper ring,and the inner ring is positioned within and supported by the firstrecess and the second recess so that an upper surface of the inner ringand an upper surface of the outer ring are co-planar.
 2. The substratesupport assembly of claim 1, wherein the inner ring is fabricated fromsilicon.
 3. The substrate support assembly of claim 1, wherein the outerring is fabricated from quartz.
 4. The substrate support assembly ofclaim 1, wherein the upper surface of the inner ring has a plurality ofprotrusions disposed symmetrically around a circumference of the innerring.
 5. The substrate support assembly of claim 1, further comprising:a pumping ring disposed over the outer ring.
 6. The substrate supportassembly of claim 5, wherein the pumping ring has a plurality ofprotrusions disposed at a bottom surface of the pumping ring.
 7. Thesubstrate support assembly of claim 1, wherein a top surface of thefirst recess and a top surface of the second recess are at a sameelevation.
 8. An substrate support assembly for processing a substrate,the substrate support assembly comprising: a substrate support; anelectrostatic chuck disposed on the substrate support, wherein theelectrostatic chuck comprises a first recess formed in an upper portionof the electrostatic chuck; and a process kit surrounding theelectrostatic chuck, wherein the process kit comprises: an inner ring;an outer ring disposed radially outward of the inner ring, wherein theouter ring comprises a second recess formed in an upper portion of anupper ring, wherein the inner ring is positioned within and supported bythe first recess and the second recess, and an upper surface of theouter ring is higher than an upper surface of the inner ring; and aplurality of pumping channels formed through the outer ring, wherein thepumping channels are angled downwardly towards a direction away from theinner ring.
 9. The substrate support assembly of claim 8, wherein theinner ring is fabricated from silicon.
 10. The substrate supportassembly of claim 8, wherein the outer ring is fabricated from quartz.11. The substrate support assembly of claim 8, wherein the upper surfaceof the inner ring has a plurality of protrusions disposed symmetricallyaround a circumference of the inner ring.
 12. The substrate supportassembly of claim 8, wherein a longitudinal direction of the pumpingchannels is at an angle with respect to a direction extending along anouter peripheral surface of the outer ring.
 13. The substrate supportassembly of claim 12, wherein the angle is in a range of about 30degrees to about 88 degrees.
 14. The substrate support assembly of claim8, further comprising: a cover ring disposed over the outer ring. 15.The substrate support assembly of claim 14, wherein the cover ring isfabricated from quartz or silicon.
 16. A method of removing particlesfrom a substrate support surface, comprising: arrange a top surface ofan outer ring coplanar with a top surface of an inner ring, an outerring disposed radially outward of the inner ring, the outer ringincluding a first upper surface and a second upper surface, whereinfirst upper surface is co-planar with the upper surface of the innerring; symmetrically arrange a plurality of protrusions on an inner ringfor positioning a substrate on a substrate surface; provide pumpingchannels on the outer ring, the pumping channels configured to pumpunwanted material away from the substrate support.
 17. The methodrecited in claim 16, further comprising: positioning a portion of eachpumping channel at an acute angle below a bottom surface of thesubstrate.
 18. The method recited in claim 16, further comprising:provide a slanted surface in the outer ring at an acute angle below thetop surface of the outer ring.
 19. The method recited in claim 16,wherein the pumping channels are provided through a surface of the outerring.
 20. The method recited in claim 16, further comprising: arranginga cover ring above the outer ring.